HM5661 [HMSEMI]
37V Step-Up LED Driver with PWM to Constant Current;
| 型号： | HM5661 |
| 厂家： | 
H&M Semiconductor |
| 描述： | 37V Step-Up LED Driver with PWM to Constant Current |
| 文件： | 总13页 (文件大小：799K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
HM5661
Current
HM5661
37V Step-Up LED Driver with PWM to Constant
Dimming
Mode
Fea
t
ur
e
s
Descriptions
HM5661 is a serial white LED driver, featuring an
architecture of 86% high-efficiency current od
boost converter, driving up to 10 serial LEDs or a
Drive up to 10 serial
PWM to Constant Current dimming
Integrated 40V high current
(1.3A li
Wide VIN Input Range: 2.7V~5.5V
Dimming scheme up to 100:1 ng
cy
LEDs
m
e
mode
switch
3x13(3LEDs in rows) LED matrix. And it
PWM to Constant Current dimming control
a
dop
ode,
Hz
t
s
mit)
m
with wide frequency range from 200Hz to 200
(The dimming frequency above 10kHz
k
r
a
e
is
es
he
Up to 86% PWM converter
Low 200mV feedback
Eff
i
c
i
e
n
recommended). The serial configuration
the very most brightness consistency of
whole LED
assur
v
o
l
ta
g
e
t
LED open-circuit (OVP) protection: 37V
High switching frequency: 1.1MHz
array.
For Compact Solution Size
HM5661 works on 1.1MHz switching
which can maximize current output of 1.3A li
and achieve high current conversion
and result in external compact component size.
frequency,
Integrated Soft
s
t
a
rt
mit
< 1µA shutdown
c
u
rre
n
t
efficiency
Compact SOT23-6, TSOT23-6, DFN-6 Pack
Green
-40 to +85 ˚C Temperature
age
compliant
Additionally, the
number is
t
o
t
a
l
external
component
ra
ng
e
m
i
n
i
m
i
ze
d
due to the integrated
A
pplications
t
low-side power MOSFET.
LED
b
a
ckligh
i
ng
HM5661 integrates multiple protection
such as LED open-circuit protection,
f
ea
t
u
r
e
s
,
l
Mobile
Phon
e
s
therm
a
Handheld De
v
ic
e
s
shutdown protection and cycle-by-cycle
current limit protection. And the built-in soft
i
npu
t
t
Digital Photo
F
rames
star
Automotive Navigation
circuit limits inrush current when the
circuit
starts.
Ordering Information
Order Part
Nu
m
b
e
r
Top Ma
rk
i
ng
TA
Package
HM5661MR
HM5661TMR
HM5661DR
61YW
61YW
D61
Green
Green
Green
-40 to +85°C
-40 to +85°C
-40 to +85°C
SOT23-6
TSOT23-6
DFN2*2-6
Tape & Reel, 3000
Tape & Reel, 3000
Tape & Reel, 3000
HM5661
Pin Assignment
TSOT23-6/SOT23-6
DFN2*2-6
LX
1
6
VIN
1
2
FB
8
5
VIN
EN
LX
NC
GND
2
5
4
NC
EN
GND
FB
3
4
GND
3
Figure 1 Top View
Pin Descriptions
Na
m
e
Description
LX
Converter switching node
Converter/IC ground
GND
FB
Output feedback pin regulated at 0.2V
EN
NC
VIN
IC enable and PWM dimming control pin
No connected
IC supply voltage
HM5661
Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Rating” may cause permanent damage to the device. These are stress
ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections
of the specifications is not implied. Exposure to absolute maxim rating conditions for extended periods may affect device reliability.
Pa
r
a
m
e
te
r
Ra
t
i
ng
Unit
Supply Voltage / VIN
High Voltage Nodes / LX
Other pins / FB, EN
-0.3 to 6.0
-0.3 to 40
-0.3 to VIN + 0.3
-40 to 150
-65 to 150
300
V
V
V
Operating Temperature Range / TJ
Storage Temperature Range / TS
Lead Temperature Range / TLEAD
°C
°C
°C
SOT23-6/TSOT23-6
DFN2*2-6
190
Thermal Resistance / θJA
°C/W
140
Maximum Power Dissipation at TA<25°C
0.526
W
HBM, JEDEC: JESD22-A114
4
2
kV
ESD
CDM, JEDEC: JESD22-C101
kV
Recommend Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended Operating
conditions are specified to ensure optimal performance to the datasheet specifications. DIOO does not Recommend exceeding them
or designing to Absolute Maximum Ratings.
Pa
r
a
m
e
te
r
Ra
t
i
ng
Unit
Supply Voltage
Operating Temperature Range
2.7 to 5.5
-40 to 85
V
°C
HM5661
Electrical Characteristics
Typical value: Vcc=3.6V, TA = 25°C, unless otherwise specified.
S
ym
bo
l
Pa
r
a
m
e
te
r
Cond
i
t
i
on
s
M
in
.
Typ
.
Ma
x
.
Un
i
t
IC Supp
l
y
VIN
2.7
5.5
V
V
Input operating range
UVLO hysteresis
UVLOHYST
0.22
0.22
0.67
mA
mA
µA
IC quiescent current(non switching)
IC quiescent current(switching)
VIN pin shutdown current
FB=0.4V
FB=0V
IQ
ISHDN
Boost Conv
FB
0.1
EN=GND
erter
0.196
0.2
0.1
0.4
0.1
0.204
V
µA
Ω
FB pin accuracy
IFB
FB pin bias current
NMOS on-resistance
LX pin leakage current
RDS(ON)
ILX
ILIM
FSW
µA
A
1.0
1.3
1.1
95
1.6
39
Peak NMOS current limit
Oscillator frequency
Maximum duty cycle
MHz
%
DMAX
Over voltage threshold,
Measured at VOUT pin
OVP
TS
37
1
V
ms
Start-up time
Logic Signal
VTH-L
0.4
V
V
Logic low threshold
VTH-H
TOFF
FEN
1.4
0.2
Logic high threshold
2
ms
kHz
°C
°C
EN low to shutdown time
Dimming frequency
200
146
19
IC junction thermal shutdown threshold
IC junction thermal shutdown hysteresis
TJ-TH
Specifications subject to change without notice.
HM5661
Application Circuit
In typical application, HM5661 is competent in the below two configurations: 10 series LED-Array and 3(row)x13
LED Matrix. As depicted in following figures:
22μH
Input
Power:
2.7V-5.5V
L1
D1
C1
C2
10µF
0.47µF
LX
VIN
EN
NC
HM5661
E
nable
Duty Cycle
FB
VFB
RFB
GND
10Ω
PWM dimming signal
Figure 2. 10 Series LED Array Application Circuit Configuration
22μH
Input Power:
2.7V-5.5V
L1
D1
C1
C2
2.2µF
10µF
LX
NC
VIN
EN
HM5661
Enable
Duty Cycle
FB
VFB
GND
RFB/13
PWM dimming signal
Figure 3. 3x13 (3 LEDs in row) LED Matrix Application Circuit
Configuration
Note: A 22µH inductor is recommended for HM5661.
HM5661
Functional Block Diagraph
VIINN
LX
LX
Thermal
Shutdown
2ms Delay
Over voltage
Shutdown
protection
Input Logic and
Low Pass Filter
Voltage Reference
EN
EN
0-200mV
PWM
Control and
Gate Drive
EA
FB
FB
COMP
Current
Sense
∑
Current
ense
S
l
e
o
n
p
s
e
a
Current
Limit
Oscillator
C
o
m
p
t
i
o
n
GND
GND
Figure 4. Functional Block Diagraph
HM5661
Operation Principle
HM5661 utilizes a constant frequency current-mode boost converter architecture to power white LED strings or
arrays by pumping current precisely regulated by feedback voltage VFB and feedback resistor RFB, illustrated in
Figure 6, Page 8.
As illuminated in the Functional Block Diagraph above, PWM Control and Gate Drive Block periodically opens
and closes the Power MOSFET synchronized with Oscillator. At the rising edge of Oscillator pulse, Power
MOSFET is turned on, while closed when the comparator tells the Current Sense slope ramp goes above the
output "difference" of error amplifier EA. The Current Sense slope ramp is generated by Current Sense from
sampling inductor charging current and compensated by Slope Compensation. And the output "difference"
comes from comparing feedback voltage VFB with internal reference voltage VREF by Error Amplifier EA. Both the
two close loops assure the output current stabilization and make feedback voltage VFB in consistency with
reference voltage VREF. and we will see in the next section that the IC dims LEDs by regulating the reference
voltage.
HM5661 integrates soft-start to limit the inrush current on the output. And HM5661 also features internal
protection circuits such as over-voltage protection (OVP), cycle-by-cycle current limit protection and thermal
shutdown.
HM5661 adopts PWM dimming control by regulating the reference voltage. The PWM signals through a
low-pass filter, then transfer to an analog reference voltage.(PWM to Constant Current Mode). Pin EN listens
PWM signals from 200Hz to 200kHz. Once powered on, the HM5661 gradually soft starts to output LED current
proportional to the PWM signal duty cycle. A 100% duty cycle PWM signal leads the IC to maximum current
output. And a 0% duty cycle PWM signal or a 2ms long low pulse will shutdown the IC. Any non-0% duty cycle
PWM signal to Pin EN will arouse the IC again. Dimming scheme up to 100:1 range.
All the dimming process could be explained in detail that, the output LED current is controlled by the internal
feedback voltage VFB, as illustrated in the following Application Notes- LED current Setting Section. And the value
of VFB (from 0 to 200mV) is absolutely proportional to the duty cycle of PWM signal (from 0% to 100%). More is
depicted in the below figure.
Figure 5. Duty cycle of PWM signal vs. Reference Voltage VREF
HM5661
Application Notes:
MAX LED Current Settings
LED Current is determined by the current through the
feedback resistor RFB, as depicted in the right-hand
figure. VFB is a high-impedance state input feedback
voltage, so no current goes through Pin FB and the
built-in "boost" DC/DC has to pump current to feed
IFB.
L
X
IL
ED
VIN
EN
NC
HM5661
ILED=IFB=VFB/RFB
I=0
FB
VFB equals to VREF which is internally set to a
maximum value of 200mV. So
VF
B
RFB
IF
GND
B
ILED(MAX) = 200mV / RFB
For LED current accuracy, 1% precision resistor is
recommended.
Figure 6. ILED Max Calculation
Feedback Voltage VFB Calculation
The feedback voltage VFB is regulated by the internal reference voltage VREF, which is in detail described in
Figure 5. So the VFB is approximately same as VREF in the timing, except for that VFB always has a delay with
respect to VREF since both in the start-up or the dimming process, the system takes time to adjust VFB equal to
VREF. if we neglect these delays, VFB changes with Pin EN signal just as the VREF
.
Recommended LED Dimming Method for 10-LEDs series
EN pin PWM signal dimming
Application
The principle of PWM dimming control is explained in detail above. A certain duty cycle PWM signal to EN pin will
reset the reference voltage VREF, which will in turn determine the LED current. If we set RFB = 10.0Ω, so
ILED(MAX)=20mA, then we have ILED changes with the PWM duty cycle as the following:
Figure 7. Duty cycle of PWM signal vs. LED Current
HM5661
Inductor Selection
A 10µH~22µH inductor is recommended for both 10-LED serial string and 3x13 LED matrix application. A low
DCR inductor could be suggested if a high efficiency is critical. The inductor's saturation current rating should
also exceed the peak input current, especially for high load current application such as 3x13 matrix.
Table 1. Inductor Se
DCR( Min. Se
qu
lector
Inductor(µH)
100 Hz,1V
Ω
)
lf-r
e
s
on
an
t
Saturation Heat Rating
Part Number
@
K
+/-30%
0.029
F
r
e
en
cy(MHz)
C
u
rre
n
t
(A)
Current(A)
SWPA8040S100MT
SWPA8040S220MT
10+/-20%
15
3.60
3.30
22+/-20%
0.069
9.5
2.40
2.10
The Calculation Forluma of Inductor Peak to Peak (Ipp):
Vin × D
IPP =
L × F
S
The Calculation Forluma of The Cycle Duty:
ton Vout +Vf −Vin
D =
=
T
S
Vout +Vf
Vin : The voltage of Input
Ipp : Inductor Peak to Peak
L : The Inductor Value
Vf : The forward bias voltage of Schottky diode
Fs : Switching frequency（1/Ts）
Vout : The voltage of Output
The Calculation Forluma of The Inductor Peak current:
Ipp Vout Iout
Vin × D
Ipeak = lin +
+
+
2
Vin
η
2× L × Fs
Capacitor Selection
Small size ceramic capacitors are recommended for HM5661 application. A 10µF input capacitor and a 0.47µF
output capacitor are recommended for 10/8/6-Series LED applications. Larger value output capacitors like 2.2µF
are recommended in higher output current applications to minimize output ripple. Ceramic capacitor Vendors
such as Murata, AVX, Taiyo Yuden are recommended.
Diode Selection
Since HM5661's low forward voltage drop and fast reverse recovery time, a schottky diode is recommended.
The current rating of the schottky diode should exceed the peak current of the boost converter. The voltage rating
should also exceed the target output voltage.
HM5661
Table 2. Diode Selector
Sc
hottky
F
o
rw
a
rd
F
o
rw
a
rd
Re
v
e
rse
Appli
c
a
t
ion
s
Di
od
e
Vo
l
t
a
g
e/
Cu
rre
n
t
Vo
l
t
a
g
e
Manufacturer
Part
Nu
m
b
e
r
V
m
A
V
20mA, 8/10 Serial LEDs
37V OVP
PMEG6010CEJ
0.57
1000
60
NXP
PCB Layout Design Recommendation
As for all switching power supplies, especially those high frequency and high current ones, layout is an important
design step. If layout is not carefully done, the regulator could suffer from instability as well as noise problems. To
reduce switching losses, the LX pin rise and fall times are made as short as possible. To prevent radiation of high
frequency resonance problems, proper layout of the high frequency switching path is essential. Minimize the
length and area of all traces connected to the LX pin and always use a ground plane under the switching
regulator to minimize inter-plane coupling. The loop including the PWM switch, Schottky diode, and output
capacitor, contains high current rising and falling in nanosecond and should be kept as short as possible. The
input capacitor needs not only to be close to the VIN pin, but also to the GND pi in order to reduce the IC supply
ripple. Figure 8 shows a sample layout.
Figure 8. PCB Layout recommended
HM5661
Physical Dimensions: SOT-23-6
COMMON DIMENSIONS
(UNITS OF MEASURE=MILLIMETER)
S
ym
bo
l
MIN
NOM
MAX
A
A1
A2
A3
b
-
-
1.25
0.15
1.20
0.70
0.50
0.45
0.20
0.16
3.026
3.00
1.726
1.00
2.00
0.60
0
-
1.00
0.60
0.36
0.36
0.14
0.14
2.826
2.60
1.526
0.90
1.80
0.35
1.10
0.65
-
b1
c
0.38
-
0.15
2.926
2.80
1.626
0.95
1.90
0.45
0.59REF
0.25BSC
-
c1
D
E
E1
e
e1
L
L1
L2
R
0.10
0.10
0°
-
0.25
8°
R1
Θ
-
-
Θ1
Θ2
3°
5°
7°
6°
-
14°
HM5661
Physical Dimensions: TSOT-23-6
COMMON DIMENSIONS
(UNITS OF MEASURE=MILLIMETER)
S
ym
bo
l
MIN
NOM
MAX
A
A1
A2
A3
b
-
-
0.90
0.15
0.85
0.45
0.50
0.45
0.20
0.16
3.05
3.00
1.70
1.00
2.00
0.60
0
-
0.75
0.40
-
0.65
0.35
0.36
0.36
0.14
0.14
2.85
2.60
1.60
0.90
1.80
0.30
b1
c
0.38
-
c1
D
0.15
2.95
2.80
1.65
0.95
1.90
0.45
0.575REF
0.25BSC
-
E
E1
e
e1
L
L1
L2
R
-
-
0.25
0.25
8°
R1
Θ
-
0°
3°
10°
-
Θ1
Θ2
5°
7°
12°
14°
HM5661
Physical Dimensions: DFN-6 2*2
COMMON DIMENSIONS
(UNITS OF MEASURE=MILLIMETER)
Symbol
MIN
0.70
0
NOM
0.75
MAX
0.80
0.05
A
A1
A3
b
0.02
0.20REF
0.30
0.25
1.90
1.90
0.90
1.50
0.55
0.15
0.20
0.35
2.10
2.10
1.10
1.70
0.75
0.35
0.30
D
2.00
E
2.00
D2
E2
e
1.00
1.60
0.65
K
0.25
L
0.25
H
0.20REF
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